Programme check · Missing links
Missing links in a P6 programme — open ends, and why the float is wrong without them
Every activity needs a predecessor and a successor. What P6 counts as an open end, why imported and progressed programmes lose links, how to find them, and what to link to.
What P6 counts
The Check Schedule Report lists every incomplete activity with no predecessor, no successor, or neither. The first activity and the finish milestone are the only legitimate open ends; the DCMA target is that no more than 5% of activities are missing either.
Level-of-effort activities and WBS summaries are excluded from the count. Milestones are not: a milestone with nothing feeding it is a date somebody typed.
Why it matters more than any other check
An activity with no successor can slip for a year without moving the project finish, because nothing is downstream of it. Its float is the whole remaining programme. The critical path runs around it. Every number the schedule produces after that — float, driving path, forecast finish — is computed on the assumption that the links are real, and if they are not, the numbers are not.
On the real programmes put through the free check so far, roughly half as many links as activities has been normal. Half the activities in those files are floating. That is not a network; it is a list with dates on.
Where the links go
- Imports. An Asta or MS Project file whose links were drawn to summary bars arrives in P6 with the summaries gone and the links with them.
- Progress by typing. Updating a programme by overwriting dates rather than by statusing activities leaves the logic behind; after a few months of it, the links no longer describe the work.
- Sections planned in isolation. A trade or a floor built as its own chain and never joined to the one before it.
How to find them
Press F9 and read the Schedule Log: it lists activities without predecessors and without successors by ID. Or, in the Activities view, filter on Predecessors is empty, then on Successors is empty. Group by WBS to see which sections were never joined up.
What to link to
The first piece of work that cannot start until this one is done. Not the finish milestone — that produces high float instead of an open end and solves nothing. Not the section summary. The activity.
Where an activity genuinely has no successor — a close-out item, an as-built drawing — link it to the completion milestone and record that it was deliberate. A link with a reason is a decision; a missing one is a gap.
Run it on your own file
The free check runs this and eleven more of P6’s Check Schedule Report checks on an Asta, P6 or MS Project file, in your browser. Nothing is uploaded and there is no account. Drop a programme in.
Related: High float · Negative float